First go to http://www.7-zip.org/
Download 7zip, its safe dont worry. Now right click on the .rar folder and you should see a "7-zip" or something like it. Choose the option with extract in it, and do it to where ever. Now open up the extracted battlefront extreme folder and it should have a readme which will explain how to install the mod, if not post again and Ill dig that up for you.

"Everyone that posts here is aware of the game, thanks though." ET
"It is Lucasarts"~ LordJhredmo